The head of the Mayor's Office of Information Technology has been placed on paid leave indefinitely as Baltimore's inspector general investigates allegations that the department made payments to contractual employees for work they may not have performed, city officials confirmed Tuesday.

Chris Tonjes, the mayor's chief of information technology, was ordered Monday to take administrative leave for the duration of the investigation, said Kevin Harris, a spokesman for Mayor Stephanie Rawlings-Blake.

Harris said Tonjes' leave is a routine step. "This is typical in an investigation of this nature and does not indicate guilt of any kind," Harris said.

He said the administration moved within days of a request by city Inspector General Robert H. Pearre Jr. that Tonjes be placed on leave.

Rawlings-Blake announced last week that she had directed Pearre to investigate the department amid "very serious allegations of fraud and abuse." Pearre, a former FBI agent and chief investigator for the House Appropriations Committee in Washington, joined the city in May.

I am not sure, this seems like a good way to get rid of another CIO and leave the deadwood behind. Given that it appears as if he has been trying to make changes, people are awefully quick to dump on him with really no facts. Since I moved to the area (Catonsville) in 1975 the population of the...

Tonjes, who was paid $139,700 last year, did not respond to a request for comment.

Pearre declined to comment Tuesday, citing the ongoing investigation. He said the probe should be complete in "a matter of weeks."

"The investigation is progressing, but as in the case of all of our ongoing matters, we do not comment on investigative details," Pearre said.

Rawlings-Blake has provided little detail on the potential problems, though she did say the allegations came from more than one source. The investigation is focused on whether work was completed and whether it was performed by the individuals who were paid, according to the administration.

Harris has said the investigation will center on contractual work during the past 18 months. He said three companies have provided contractual workers during that period: Digicon, which has offices in Rockville and Virginia; Windbourne Consulting LLC, which has an office in Washington, among other cities; and Telecommunications Systems Inc., an international firm headquartered in Annapolis.

Jerome Mullen, the deputy chief of the information office, will serve as acting chief, Harris said.

Contractual workers make up a large part of the information technology office's workforce, although the number of contractual workers employed during the past 18 months wasn't immediately clear. The office has a $37 million budget and 306 city employees.

Harris said Pearre asked the mayor late last week to place Tonjes on leave, and the administration began to make arrangements to ensure that an acting chief information officer was ready to stand in and continue the department's operations "as smoothly as possible."

Tonjes was hired in July 2012 amid a previous inspector general's investigation of the information technology office. He had served as chief information officer for the District of Columbia Public Library.

He replaced Rico J. Singleton, who resigned after an audit in New York detailed ethics violations while he worked in that state's government. The violations included negotiating a job for his girlfriend and soliciting a job for himself with a software vendor that was awarded a major contract.

Baltimore's previous inspector general, David N. McClintock, issued a report in September 2012 that was highly critical of the information technology office. He found that the office was quietly using an existing contract to spend nearly $675,000 to upgrade the city government's phone and computer equipment without a new bidding process. McClintock's investigation found that the department also misled the City Council president about the project.

Rawlings-Blake has been at odds with Comptroller Joan M. Pratt over how to replace the city's outdated municipal phone system, which lacks basic features such as call waiting, caller ID and voice mail alerts.